Crankcase ventilation



Feb. 22, 1955 J. KEYLWERT 2,702,534

CRANKCASE VENTILATION Filed May 8, 1952 2 Sheets-Sheet l iff/G. 7

Feb. 22, 1955 J. KEYLWERT CRANKCASE VENTILATION 2 Sheets-Sheet 2 Filed May 8, 1952 United States Patent CRANKCASE VENTILATION Johann Keylwert, Koln-Kalk, Germany, assignor to Klockner-Humboldt-Deutz Aktiengesellschaft, Koln, Germany Application May 8, 1952, Serial No. 286,741

Claims priority, application Germany May 8, 1951 8 Claims. (Cl. 123-41.86)

The present invention relates to internal-combustion engines and, more particularly, concerns a crank-case ventilation for a piston actuated internal-combustion engine which has a receiving chamber for cooling air, scavenging air, or charging air.

lnasmuch as practical tests with internal-combustion engines have shown that it is of great advantage to ventilate the crank-case, it is an object of the present invention to provide a simple ventilation of the crankcase of piston actuated internal-combustion engines.

It is another object of this invention to provide a crank-case ventilation for internal-combustion engines which simultaneously will make it possible that the quantity of oil which collects in the corners formed by the outer casing walls of the engine and the upper crankcase wall adjacent the lower end of the respective cylinder tube or liner will be kept at a minimum.

lt is still another object of this invention to provide means for separating oil from the air to be used for Ventilating the crank-case chamber.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawings in which:

Figure 1 is a cross section through a two-stroke cycle internal-combustion engine having its cylinders arranged in V-form.

Figure 2 is a section taken along the line Il-II of Figure 1.

Figure 3 represents a section taken along the line Ill-lll of Figure 2.

Figure 4 illustrates a detail on a scale materially larger than the scale used in connection with Figures l, 2 and 3.

General arrangement The problem underlying the present invention and set forth above, namely, the provision of a simple arrangement for Ventilating the crank-case of internal-combustion engines has been solved according to the present invention by connecting the receiving chamber for cooling air, scavenging air, or charging air through an opening or passage, preferably a choke, with the crank-case which latter in a manner known per se is provided with an air outlet.

According to a further development of the invention, the said opening or passage also communicates with pipe or conduit means extending into the corners formed by the outer casing walls of the engine and the upper crankcase wall adjacent the lower end of the respective cylinder tube or liner so that the major quantity of the oil accumulating in said corners will be drawn olf, while an oil separator is provided to separate the oil from the air to be used for Ventilating the crank-case.

Structural arrangement Referring now to the drawings in detail, the structure shown in Figures 1 to 3 concerns a two-stroke cycle internal-combustion engine which has two cylinder rows 1 and 2 arranged in V-form. Provided between the said cylinder rows 1 and 2 is a receiving chamber 3 for the scavenging air. As will be clear from Figure 2, the twostroke cycle internal-combustion engine is provided with a one-sided reversing scavenging arrangement. The outlet passages are designated wiwth the reference numeral 4 while the inlet passages are designated with the reference numeral 5. The space or chamber 6, surrounding 2,702,534 Patented Feb. 22, 1955 ICC the inlet passages 5 and located outside the cylinders in the cylinder rows, communicates with the scavenging air receiving chamber 3 so that the scavenging means can pass in the shortest way through the passages 5 into the cylinder. Connected to the outlet passages 4 are the outlet conduits 7 which pass through the upper wall 8 of the scavenging air receiving chamber 3 upwardly toward the outside. The two-stroke cycle internal-combustion engine is so designed that the cylinder tubes or liners 9 are inserted into an extension of the casing 11 which extension extends up to the cylinder heads 10. The cylinder tubes or liners 9 are suspended from the cylinder heads 10 which latter by means of bolts 12 extending into the crank-case 13 are connected to the machine casing 11. The lower ends of the cylinder tubes or liners 9 are adjustably held in the walls 14 which with a wall 15 form the upper wall of the crank-case 13.

The two-stroke cycle internal-combustion engine is characterized in that the scavenging air receiving chamber 3 is connected through an opening 16 with the crank chamber 17 of the crank-case 13. The crank chamber 17 is in a manner known per se connected with the outer atmosphere through an outlet connection 18. The opening 16 is located at the lowest spot of the scavenging air receiving chamber 3 or the substantially V-shaped chamber formed by the two cylinder rows 1 and 2.

With two-stroke cycle internal-combustion engines of the type illustrated in the drawing it has been found that, if the oil is not properly stripped ol from the pistons, oil will collect in the corners formed by the outer casing walls 19 and the walls 14. This oil is under certain operating conditions of the engine returned together with the scavenging air into the cylinder, and 'there the greatest part of this oil is burned or is 10st through the exhaust.

According to a further development of the invention, and in order to overcome the last-mentioned drawback, pipes 2l) are provided which extend into the said corners and communicate with the opening 16. The pressure of the scavenging air causes the oil to pass from the said corners through pipes 20 and the opening 16 into the crank chamber 17. The scavenging air takes care that only a minimum of oil is present in the said corners. A part of the scavenging air passes through pipes 20 and the opening 16 into the crank chamber 17 and ventilates the same while a continuous air stream passes from the said crank chamber 17 through the discharge connection 18 toward the outside. In order to p revent that too much scavenging air passes in the described manner toward the outside, the opening 16 is constructed as a choke opening.

In order to separate the lubricating oil which enters the\crank chamber 17 with the scavenging air through the tubes 20 and the opening 16, the opening 16 has from the interior of the crank chamber 17 connected thereto a device 21 which simultaneously acts as choke and as oil separator. This device is shown in Figure 4 on an enlarged scale and consists primarily of a casing 22 provided in the interior thereof with sheet metal discs 23, 24 or the like. These discs create a labyrinth-like passage. For instance, the disc 23 may have a central opening 23 and the disc 24 may have an eccentric opening 24.

lf non-filtered air, for instance, cooling air, is used for Ventilating the crank chamber, it is preferable to provide the opening 16 with a lilter 25.

While in connection with the structure shown in the drawing, the receiving chamber 3 has been described as receiving the scavenging air, it is, of course, understood that the present invention is by no means limited to the use of scavenging air for Ventilating the crank chamber. If desired, the invention may also be used in connection with internal-combustion engines having a receiving chamber for cooling or charging air. In other words, cooling or charging air may then be passed into the crank-case for Ventilating the same.

It is also to be understood that the present invention is by no means limited to the particular construction shown in the drawings but also comprises any modifications within the scope of the appended claims.

What I claim is:

1. An arrangement for Ventilating the crank-case of a two-stroke cycle internal-combustion engine having its cylinder arranged in V-form and being provided with a V-shaped chamber adapted to receive scavenging air, which comprises in combination, an opening arranged at substantially the lowest spot of said V-shaped chamber and adapted to effect communication between said chamber and said crankcase, and an air outlet connection connected to said crank-case for exhausting air used for Ventilating said crank-case.

2. An arrangement for Ventilating the crank-case oi' a two-stroke cycle internal-combustion engine which comprises in combination, a plurality of cylinders arranged in V-form, a V-shaped chamber adapted to receive scavenging air and located between said cylinders, an engine casing having an extension extending up to the heads of said cylinders and having wall portions connected to the bottom of said chamber, cylinder tubes inserted in said extensions, an opening at substantially the lowest spot of said V-shaped chamber, conduit means communicating with said opening and extending into the corners formed by the outer wall of said engine casing and the said wall portions surrounding the lower ends of said cylinder tubes.

3. An arrangement for Ventilating the crankcase of a piston actuated internal combustion engine having a plurality of cylinders which comprises in combination: an air receiving chamber directly adjacent said crank case and having a wall section in common therewith, said chamber at least partly surrounding said cylinders and being provided with a passage arranged for effecting communication between said chamber and said crankcase, choke means arranged within said crankcase and connected to said passage so as to cause air from said receiving chamber to pass through said choke means prior to entering said crankcase, and air outlet means connected to said crankcase.

4. An arrangement for Ventilating the crankcase of a piston actuated internal-combustion engine, which comprises in combination, a receiving chamber adapted to receive air, said chamber being provided with an opening adapted to effect communication between said chamber and said crank-case, a choke arranged within said crank-case and connected to said opening so as to cause air from said receiving chamber to pass through said choke prior to entering said crank-case, said choke being formed by a plurality of spaced disc means provided with passages oiset with regard to each other so as to create a labyrinth-like passage, and outlet means connected to said crank-case for exhausting air therethrough.

5. An arrangement according to claim 4, which includes tilter means interposed between the said opening and said choke.

6. An arrangement for Ventilating the crank-case of a piston actuated internal combustion engine, which comprises in combination: a cylinder block, cylinder means arranged within said block, a receiving chamber provided within said cylinder block and arranged to receive air and to convey the same to said cylinder means, restrictive passage means connecting said receiving chamber with said crank-case for conveying a restricted ow of air from said chamber to said crank-case, and air discharge means connected to said crank-case and communicating with the atmosphere to allow passage of air in a continuous ow from said receiving chamber through said crank-case into the atmosphere.

'7. An arrangement for Ventilating the crankcase of a piston actuated internal combustion engine, which comprises in combination: an engine casing including a crankcase, cylinder means within said engine casing, a receiving chamber within said engine casing and having a Wall in common with said crankcase, said receiving chamber being arranged to receive cooling or scavenging air, passage means arranged to eiect communication between said receiving chamber and the interior of said cylinder means to convey cooling or scavenging air from said receiving chamber into said cylinder means, and restrictive passage means independent of said first mentioned passage means and extending through said wall for effecting restricted communication between said receiving chamber and said crankcase, said crankcase being provided with outlet means spaced from said restrictive passage means and communicating with the atmosphere thereby being adapted to pass in a continuous stream the air conveyed from said receiving chamber through said restrictive passage means into said crankcase from the latter into the atmosphere.

8. An arrangement for Ventilating the crankcase of a piston actuated internal combustion engine, which comprises in combination: cylinder means, a receiving chamber at least partially surrounding said cylinder means and having a wall integral with said crankcase and arranged to receive charging air, passage means arranged to effect communication between said receiving chamber and the interior of said cylinder means for conveying charging air from said receiving chamber into said cylinder means, and restrictive passage means independent of and separate from said first mentioned passage means and extending through said wall for effecting restricted communication between said receiving chamber and said crank-case, said crank-case being provided with outlet means spaced from said restrictive passage means and communicating with the atmosphere thereby being adapted to pass in a continuous stream the air conveyed from said receiving chamber through said restrictive passage means into said crank-case from the latter into the atmosphere.

References Cited in the tile of this patent UNITED STATES PATENTS 1,751,910 Dozier Mar. 25, 1930 1,893,183 Sletfel Jan. 3, 1933 2,252,974 Lowther Aug. 19, 1941 2,547,587 Lowther Apr. 3, 1951 FOREIGN PATENTS 484,204 Germany Oct. 10, 1929 540,910 Germany Dec. 31, 1931 661,649 Great Britain Dec. 13, 1949 

